#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <pthread.h>

// 传递连接参数的信息结构体，将客户端的连接信息存储到结构体里面
struct SockInfo{
    struct sockaddr_in caddr;
    int cfd;
};

// 可以创建一个结构体数组用于存放客户端的连接信息，数组容量即是可以接受的最大的客户端连接
struct SockInfo infos[512];

void* working(void* arg);

int main(int argc, char const *argv[])
{
    // 1.创建监听的套接字
    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if(fd == -1){
        perror("server listen socket create failed");
        return -1;
    }

    printf("create server socket succesed\n");

    // 2.绑定本地的ip地址和port端口号
    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    saddr.sin_addr.s_addr = INADDR_ANY;
    saddr.sin_port = htons(9999);
    int ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
    if(ret == -1){
        perror("server listen socket bind host failed");
        return -1;
    }

    printf("server bind localhost ip and port(sockaddr_in) successed\n");

    // 3.设置监听, linux系统中最大监听socket的连接数是128
    ret = listen(fd, 128);
    if(ret == -1){
        perror("sever listen failed");
        return -1;
    }

    printf("server listen successed\n");

    // 初始化结构体数组
    int max = sizeof(infos)/sizeof(infos[0]);
    for(int i=0; i<max; i++){
        memset(&infos[i], 0, sizeof(infos[i]));
        infos[i].cfd = -1;
    }
 
    // accept是阻塞函数，在循环里不断的等待客户端的连接解除阻塞并建立连接
    while(1){
        struct SockInfo* pInfo;
        for (int i = 0; i < max; i++)
        {
            if(infos[i].cfd == -1){
                pInfo = &infos[i];
                break;
            }
        }
        

        // 4.阻塞并等待客户端的连接
        int caddrlen = sizeof(struct sockaddr_in);
        int cfd = accept(fd, (struct sockaddr*)&pInfo->caddr, &caddrlen);
        if(cfd == -1){
            perror("connection failed");
            //return -1; // 直接返回 or
            break; // 中断循环，结束客户端的连接，or
            //continu; // 继续循环，等待客户端连接
        }

        pInfo->cfd = cfd;

        // 创建子线程
        pthread_t pid;
        pthread_create(&pid, NULL, working, pInfo);
        pthread_detach(pid);
    }
    
    close(fd);

    return 0;
}

void* working(void * arg){

    struct SockInfo* pInfo = (struct SockInfo*)arg;

    // 连接建立成功，打印客户端的ip和port信息
    char ip[32];
    printf("client IP: %s, Port: %d -- connection successed!\n", inet_ntop(pInfo->caddr.sin_family, &pInfo->caddr.sin_addr.s_addr, ip, sizeof(ip)), ntohs(pInfo->caddr.sin_port));

    printf("----------------------------------------------------------------------------------------------------------\n");

    int num = 0;
    // 5.通信
    while(1){
        // 接收数据
        char buff[1024];
        int len = recv(pInfo->cfd, buff, sizeof(buff), 0);
        if(len > 0){
            printf("client say: %s\n", buff);
            memset(buff, 0, sizeof(buff));
            sprintf(buff, "hello, client...%d\n", num++);
            printf("server: %s\n", buff);
            send(pInfo->cfd, buff, strlen(buff)+1, 0);
        }else if(len == 0){
            printf("client IP: %s, Port: %d -- has disconnect.\n", inet_ntop(pInfo->caddr.sin_family, &pInfo->caddr.sin_addr.s_addr, ip, sizeof(ip)), ntohs(pInfo->caddr.sin_port));
            break;
        }else{
            perror("call recv fail.");
            break;
        }
    }

    // 6.关闭文件描述符
    close(pInfo->cfd);
    pInfo->cfd = -1; // 将pInfo指针指向的SockInfo数组中的SockInfo结构体的文件描述符置为-1，以在后续连接中重新赋值

    return NULL;
}